AES E-Library

AES E-Library

Two-Port Representation of the Connection between Horn Driver and Horn

A method for measuring and describing horn drivers and horns as independent parts was investigated. It is shown that the well-known two-port representation can be adopted for system characterization considering certain assumptions and limitations. The horn driver is represented as a two-port whereas the horn is characterized by its acoustical input impedance and, due to its three-dimensional sound radiation, by its on-axis transfer function and a relative directivity. With both sets of parameters the electrical input impedance, the transfer function, and the directivity of any horn driver/horn combination can be synthesized by a software tool without a need for measuring the real combination. This method speeds up procedures of either loudspeaker system design or the design and optimization of new horn drivers and horns, respectively. Besides the general-purpose measuring techniques, some specialized measuring equipment is required such as an impedance tube fitted to the horn throat and an anechoic chamber to record the directivity of the horn. Finally, all possible combinations of seven horn drivers and eleven horns have been studied to show the reliability of the method.